[+1]: Until your next turn, up to one target creature gets -3/-0 and its activated abilities can't be activated.
[−1]: You gain 2 life and draw a card.
[−7]: You get an emblem with "Your opponents can't untap more than two permanents during their untap steps."
Activated abilities contain a colon. They're generally written “[Cost]: [Effect].” Some keywords are activated abilities and will have colons in their reminder text.
An opponent affected by Dovin Baan's emblem chooses which two of their permanents to untap, not you.
Dovin Baan's first ability can target any creature, not just one with an activated ability. It can also be activated targeting no creature at all.