Trying to understand Vedas would be very challenging (and not recommended task IMHO).
Vedanta-sutra starts with, "athato brahma jijnasa", i.e. "Now one should inquire about Brahman - The absolute truth, the transcendental, spiritual nature". The "Now.." implies one has satisfied necessary prerequisites to understand and assimilate the knowledge (requiring a fairly high level of spiritual discipline and maturity). It is like trying to understand the mathematics behind quantum field theory with a grade school mathematics background---even if we recognize a few symbols here and there, we will most likely misunderstand its context and miss the point altogether. That is why modern scholars have failed to find much value or make sense of Vedas. I would even go as far and say in today's age it is simply not possible to develop the requisites (based on Prabhupada's and Kripalu's statements). This is a lost science.
But not all is lost. Fortunately, the true Brahamanas of yore foresaw this plight of civilization and composed Vedanta ("end or summary of Vedas") for our benefit. A good place to start would be Bhagavad Gita and then Srimad Bhagvatam.
In terms of the numerous demigods, there is no need to get overly confused. Think of it this way. This universe is just like a large corporation, with various managers, department heads, vice presidents, etc.. But these are simply posts, and with proper karma, anyone can become eligible to occupy such a post. The founder of this universe is God, which is not a post and no one could replace, but instead is the reason posts exist and are empowered by God's grace.
So who is God then? Well in Shrimad Bhagavatam (Ch 9 Canto 2, Verse 31-36) which is part of Vedanta, God speaks to Brahma. Brahma is the appointed CEO of the material creation for his lifetime (which is a very long time). Note Brahma is not God. He does not live eternally. Though the post exists eternally.
"The Personality of Godhead said: Knowledge about Me as described in the scriptures is very confidential, and it has to be realized in conjunction with devotional service. The necessary paraphernalia for that process is being explained by Me. You may take it up carefully."
"All of Me, namely My actual eternal form and My transcendental existence, qualities and activities let all be awakened within you by factual realization, out of My causeless mercy."
"Brahmā, it is I, the Personality of Godhead, who was existing before the creation, when there was nothing but Myself. Nor was there the material nature, the cause of this creation. That which you see now is also I, the Personality of Godhead, and after annihilation what remains will also be I, the Personality of Godhead."
"O Brahmā, whatever appears to be of any value, if it is without relation to Me, has no reality. Know it as My illusory energy, that reflection which appears to be in darkness."
"O Brahmā, please know that the universal elements enter into the cosmos and at the same time do not enter into the cosmos; similarly, I Myself also exist within everything created, and at the same time I am outside of everything."
"A person who is searching after the Supreme Absolute Truth, the Personality of Godhead, most certainly search for it up to this, in all circumstances, in all space and time, and both directly and indirectly."
Then in Brahma's glorification of God he says (Brahma Samhitha, Ch 5.1)
"īśvarah paramah krsnah, sac-cid-ānanda-vigrahah
anādir ādir govindah, sarva-kārana-kāranam"
Which translates to:
"Krishna who is known as Govinda is the Supreme Personality of Godhead.
He has an eternal blissful spiritual body. He is the origin of all.
He has no other origin and He is the prime cause of all causes."
It is worth noting that some may argue other interpretations of Vedas. In particular, monists believe in oneness with God and extract this interpretation from the Vedas. This interpretation is not authorized by the scriptures mentioned above, and anyone claiming to such interpretation imply they understand Vedas better than Brahma himself. Moreover, modern day Hinduism has degenerated... so you will find people worshipping Ganesha, Laxmi, etc.. Though Krishna denounces such activity directly in the Gita at numerous places, since their worship can only provide material benefits, which in the ultimate issue is not the point of life. (And btw, worshipping demigods can be a highly technical process, which requires trained brahamana scientists, so most efforts actually go in vain.)
Finally if you are interested in understanding Vedantic philosophy, cosmology and its message, I urge you to find bonafide sources. If you pray to God and your interest is sincere you will gradually start to see the complete picture, which is consistent, magnificient, all-inclusive of different religions (in their entirety), and complete.