How to to cut tile trim for a corner

[ukmercenary]

Hello

I've never tiled before and want to know how I am supposed to cut the tile trim for a right angle.
I have the mitre box but after several cuts, I still can't figure it out.

 

[mattylad]

And once you master simple corners you can try a 2 way (oooh errr missus!)

 

[ukmercenary]

Thanks but the best I can get the cuts is like this... what am i doing wrong ? or can I just fill the gap with something after?

 

[ukmercenary]

Would these fit https://www.ebay.co.uk/itm/Genesis-...250993?hash=item1cd50974b1:g:ycsAAOSws0JagdU7 a Diall trim?

 

[ukmercenary]

I figured it out if I place the trim flat down in the mitre box the cuts are clean