How to play as White against French Defence? (For beginner player)

That may be, but I wouldn't recommend it for a "beginner".

I play the French, and I hold the exchange in contempt. Nonetheless, I think the exchange variation is a good choice for a beginning player. It offers an open game with logical development and an emphasis on piece activity--all things beginners should strive for.

Despite my "contempt", I play the exchange as White in blitz and have played it with success OTB.

For a more principled approach against the French, the advance or the Steinitz variation are better.  With those, however, you will need more opening preparation. Get some experience with the exchange first.

I play the b3 French gambit, or two knights.