Dear Friend,

Let me take a simple example to answer your question...

There is a person called X....
- now Mr.X gets up early in the morning, dresses up, takes his car, goes to the market, gets all the groceries, vegetables, etc.....
- the same Mr.X then takes his two wheeler and goes to a few relative's and friend's houses, invites them for lunch.....
- the same Mr.X now wears the dress of a chef, holds different vessels, uses a cooking recipe manual, and cooks food for everyone...
- the same Mr.X when the guests arrive, dresses up as a neat host, invites them inside, makes them feel at home.....
- the same Mr.X serves plates, uses different serving utensils, and with a charming smile, serves the guest's, the delicious food....
- the same Mr.X waits with patience and strength(as he has been working from morning), till the guests finish the food and then bids them farewell in a polite manner....

now comes the interesting part...

a few of the guests start complimenting the grocery getter, saying if he had not got such nice grocery the feast wouldn't have been possible...a few others start complimenting the person who invited them, saying the humble person who invited is the best as he is the one who invited everyone..a few others start complimenting the chef saying its only because of the chef everything was possible and he is the best...a few others start complimenting the host , saying the host was the best as he treated everyone so well..and a few more start complimenting the persons who served, saying they are the most decent ones....a few others start complimenting the person who sent them off, saying it was the best way to treat a guest...

the point that all of the above guests are completely missing is that, all the different persons they think,as the best, is actually the same Mr.X.....its Mr.X who wears different clothes, uses respective instruments, performs his duty...the guests give individual compliments , only because they are under the "illusion" that Mr.X is not a single person...which is not only untrue but also meaningless

Using the above example...

There is one and only Parabramha(the Ultimate Supreme Soul)....He takes up different forms to perform respective duties...
- now Parabramha is the one, who before creation, becomes the Purusha and brings together all the ingredients(Pradhana) together
- the same Parabramha as Sri Vishnu initiates the bramhanda(Universe) and the term life
- the same Parabramha as Sri Bramha starts creation using His Vidya(knowledge) in the form of Sri Saraswathi(Veda)...
- the same Parabramha as Sri Vishnu sustains life, makes living possible with the help of His own form as Sri Lakshmi as the virtue of thhis creation
- the same Parabramha uses a little strength of His to create different devatas(demi-Gods) who are there to help us lead life
- the same Parabramha as Sri Shiva with the help of His own form called Sri Shakthi handles the load of the entire Universe and consumes it at the end....

people without any proper knowledge and those who are under the illusion of ignorance can only imagine that there are multiple Gods ...what is even more futile is to think that praying to some particular God is better than praying to others....as Sri Krishna says(in Bhagavad Gita) even such people are indirectly praying Him alone...but ofcourse in a wrong way...without actually understanding the reality...there is a beautiful subha****a(short meaningful poem) in sanskrit which says

aakashath patitat toyam yatha gachchathi saagaram
sarwa deva namaskaarama Sri Keshavam prati gachchathi...

(very rough meaning) just as the different drops of rain fall down and join different rivers, finally reach the same ocean at the end,
similarly,even if one prays to various Gods, every prayer actually goes to Him alone...

Please do let me know if it answers your question....