The front brake is just a bicycle brake so is elemantary to fix.
The rear brake is accessed by removing the braked wheel using two 5/8" AF spanners- be careful as two ball bearings will come out with the wheel so note carefully the sequence of re-assembly after cleaning & re-greasing the bearings. Inspect the brake shoes to see if they need replacing-similar BUT SIMPLER than replacing car brake shoes. To adjust the rear brake you may need a selfgrip wrench and a 10mm AF spanner, but the cable adjusters may be sufficient.