Only ME1 installs when you put play disc in. ME2 and 3 install via menu (after patch) so don't panic it doesn't ask for disc 2 straight away. Also means you can save space by not installing everything as it is BIG.
Relive the legend of Commander Shepard in the highly acclaimed Mass Effect trilogy with the Mass Effect™ Legendary Edition.
Mass Effect Legendary includes single-player base content and over 40 DLC from Mass Effect, Mass Effect 2, and Mass Effect 3 games, including promo weapons, armors, and packs – remastered and optimized for 4K Ultra HD.