first time setting 401k at work

first job that offers 401k, while configuring the settings it came out these 2 questions and I guessed and finished the application. now a month it would be $1080. half in roth half 401k

it seems I setup a roth and 401k at the same time. at almost 40 I know am late but should I reduce the roth for the 401k or cancel Roth and move all to 401k?

if I understand correctly 401k is pretax so it would be better now to put money in it and in 20 years roll over to roth ira?

correct me lol