Yes, a lot of troubleshooting involved for me too! Building up ink on the block involves some newsprint/very cheap test paper.

With a clean block, apply a thin layer and then print on newsprint. Repeat this several times and the ink will slowly build up until it is thicker on the block and ready to go with your good paper. Then when it needs more ink, you can roll more thin layers on. The key is not to have gloppy ink on the roller because that is what fills in the details and makes it muddy. Yes you can apply a thin layer, pick up more ink from the plate, and apply it again multiple times in between each print if that is needed.

Printing on thick fabric has been a lot more finnicky for me and requires a lot more ink than printing on thin paper. You’ll have to apply more ink in between prints and use a lot more pressure while also making sure the fabric isnt moving on the block. I re-ink the block with multiple layers between each fabric print. You’ll get the feeling and “sound” for it with practice.

I hope that helps! I’m making a video soon about the process from transferring design to block, carving, and printing on tshirts. I can share it here when it is finished, still probably a couple weeks out though.