It's just another rubbish altcoin, but if you really wanna mine it -

It uses the Equihash algorithm.  The same as ZCash, ZClassic, ZenCash etc.  Google EWBF miner (for Nvidia), or.... I'm not really sure what the best Equihash miner for AMD is.
Step 2.  Find a pool that supports BTG mining.  I know of none atm, but I haven't looked.

If you're a complete noob and just want to get in to mining easy, Nicehash is it.  On average it's less profitable than figuring it all out yourself and finding a good pool, but that's the price you pay for convenience I guess.  I've personally found zpool calculates hashrate and earnings really accurately.  Their fee is higher than average, prolly cos they don't rip you off behind the scenes.  Just my opinion.  Lots of pools make things so vague you can't really question what you're earning.  Nanopool was decent when ETH mining was the most profitable.  I highly doubt they'll do BTG.

No-one can easily walk you through mining.  It's not hard to figure out, but you really need to do your own legwork to get the most out of it.  There's no shortage of info out there.  Good luck.