I did my basic glider towing endorsement after a short amount of time on a Citabria - was quite some time ago. Completed the endorsement between a Supercub and a Pawnee.
Firstly - you would need approval from the club and I would imagine the "Tugmaster"....
so that would be the first place to chat. But from there you still need to find someone willing to do the endorsement with you - so you need suitable aircraft and suitable conditions. I do recall also needing some gliding experience as well - not sure what the requirements are these days.
I do recall at the time always being s*&t scared of the glider I never saw.....they are very hard to spot tail on or head on. Collisions are not unheard of. I found it particularly difficult the more gliders that got in the air at once from different clubs/ or multiple towing aircraft. Always looking for that unseen aircraft ...in the wrong spot at the wrong time....
And then there are "those" students/others that get a bit "out of shape" on the tow.....I do recall once having full nose up elevator - pulling the rope to dump the tow rope and glider ......can get ugly pretty quickly .....
From hindsight - I guess I am trying to say it is not something to be taken lightly or just for some fun - probably not out of capabilities, but maybe an un-necessary exposure to a higher risk at the experience level.
Also - it does takes someone else's generosity of time and efforts to train you.
Bit of networking, wandering around chatting to people ( if you still can in these days of security environment stuff...)....put the face to the name.....you get the gist?
Cheers