We get new peeps to do some basic tutorials for the frameworks we use (vuejs, laravel and such). Once a basic/medium understanding has been achieved then we assign them issues in gitlab, starting out small in both complexity and impact to the products and then slowly move them up the issues as they become more competent in the stack we use and the products we build.
If they so wish, they can ask for more complex issues to complete and we actively get newbies to take part in technical discussions on products/features/bugs/ethics.
Might not be the best way but certainly works for us and so far everyone has been happy.