To get started with reading the sagas I can recommend the free course on edX. It gives an introduction into the history of the icelandic sagas and introduces a lot of primary and secondary sources. I took the course a year ago and it helped tremendously.
Looks cool!
Yeah. It does not go into mythology a lot but I found it a great 10h spent to learn about the cultural background. It covers the era just before and during christianisation of Iceland so it also explains how and why Snorri Sturluson felt the need to write down everything known about norse mythology. Very cool for people like me who are interested in medieval culture but don’t have a history/literature degree because it opens up that world.