New to Dynasty. How to value future draft picks

.5 ppr Dynasty league
I am new to dynasty and don’t know how to value future draft picks. Is this deal in my favor? This is the first year of the league.

Give: Keryon Johnson
Get: 2019 first and 2020 second

I also drafted as a win later team instead of a win now team

Other RBs: Barkley, Collins, Conner, Penny, p. Lindsay and K billage