As to 'shielding', there's plenty on Mars. It's called dirt and rock. There's a high likelihood that caves are available, for one thing. In the short term, other needs may be satisfied via shipment from Earth. The initial colony can be scouted, supplied, and constructed using unmanned missions.

Longer term habitation will involve Martian agriculture. Microbes have already been developed to transform Martian soil into an arable form.

Back to the radiation question, after some quick research it's clear that as long as the living quarters are shielded (as above), a few hours of exposure a day are very low risk. The average dose rate at the Martian surface is well under 220 micrograys per day, and the levels only very rarely exceed that value. If one were out on the surface for five hours a day, the yearly dose would be less than that allowed for radiation workers in the USA. That level is considered negligible for increased cancers and other health problems.

Given that survival is assured, what's there is a new world, virtually unlimited resources, and unlimited potential.