Thanks!
The learning curve should be pretty flat with the basic features, hopefully! 
There is tackler new command which will produce ready-to-go and usable example journal, so testing is literally just running:
tackler new journal
tackler --config journal/conf/tackler.toml
Feel free to add, modify or delete transaction files under the journal/txns directory.
The default template journal created by new command is configured already so that you can use it directly with git, see Tackler's Git Primer, if you like to try it out.
The git storage is acting as virtual filesystem and when it's activated, journal is read directly from it. The git repository could be even "bare", there is no need to have working copy in case of pure git based storage.
However, it's possible to flip back and fort between file system and git storage by CLI argument, once you have run few git initialization commands outlined in the primer doc (those are just normal git init; git add; git commit stuff).
tackler --config journal/conf/tackler.toml --input.storage git
tackler --config journal/conf/tackler.toml --input.storage fs
This is really handy feature to run trial balances from working copy (file system) and official reports directly from git storage (either on your personal computer or on server after the changes has been pushed to the main repository).