I probably figured I would suss the situation out, maybe play somebody else's guitar. I had to big myself up, put the front back on for the young people.

----I'm not sure I understand the part in bold. I think he wanted to feel more self confident, but what about "put the front back on"???

Hello NG,

Possibly: "I had to make myself look more impressive and present a confident exterior for the young people".

Best wishes,

Many thanks Mr Pedantic!