Bricoler is not slang, but it’s a colloquial verb whose meaning can be tricky to translate to English. It basically means “to fiddle”, “to tinker”, to do manual labour as an amateur (not necessarily in a pejorative sense).
The derived noun, le bricolage, can be best translated as “do-it-yourself”. Hardware stores such as Castorama and Leroy Merlin are colloquially known as magasins de bricolage. It can sometimes have the meaning of “amateur work”.
J’ai réparé l’évier, mais c’est du bricolage, faudra qu’on appelle un plombier.
I fixed the sink, but it’s amateur work, we’ll have to call a plumber.
Un bricoleur is a handyman; someone who is skilled at DIY or enjoys it. The feminine form is bricoleuse.
Mon père est un gros bricoleur, il passe tous les dimanches dans le garage à réparer des trucs.
My father is a huge handyman, he spends every Sunday in the garage fixing stuff.
Une bricole, however, has a different meaning. It can mean “a little thing.”
J’ai acheté une bricole à la brocante.
I bought a trinket at the jumble sale.
But it can also mean “trouble” (in the plural).
Si tu continues, il va t’arriver des bricoles !
If you keep acting like this, you’re going to be in trouble!
Listen to the examples: