Beans want to be "shallow" (compared to corn) - generally 1/2 to 3/4" is in the ballpark. But the kicker is they also want to be in moisture with good seed to soil contact. It can be tough to get all three.
It csn be tough to maintain a constant 1/2-3/4 in depth without row cleaners. Any time the planter gage wheels roll over a cob or anything the seed depth changes.
If you have planter mounted row cleaners, set the Trashwheels depth acording to soil moisture. If there is adequate moisture for 4 or 5 days, set the Trashwheels to just skim the surface clear residue and level a path for the gage wheels. If it is dry or moisture has been worked out of the top of the soil profile, set the row cleaners down as deep as necessary to be able to plant the beans at say 3/4" but yet into moisture.
Usually you do not want to plant in a depression but with beans the important thing is to get them up and growing quickly and uniformly.
When beans are planted right you will see them all up at the same height at the same time. When they are not planted right you will see afew beans emerging here and there along the row, some 5" high some 2" high and some just peeking through - not good.
Best of Luck.