You can see all of the posts you've ever liked on Instagram by tapping on your profile icon in the bottom right, then tapping on the gear icon next to "Edit Profile." Scroll down to "Posts You've Liked" and tap on it to see all the posts you've ever liked. You can change between list and grid view with the buttons at the top.
Instagram offers several privacy settings that allow you to avoid specific people. You can block people by opening up the app on your iPhone and tapping on the target user name to bring you to their profile. Then tap the "..." button in the top right and select "Block." Verify that you want to block them and tap Block again.
There are several privacy options that you can employ on Instagram. If you only want particular friends and family to view your posts, you should make your account private. If you want to remain public, you can block specific people. Neither method will drop followers you have already picked up though, so you will need to do that manually. Launch your iPhone Instagram app and tap on the profile icon in the bottom right.
Anybody can view your Instagram posts by default, but you can make your account private so that only people you approve can follow you and see your posted photos and videos. You can't change this setting from a desktop, so you'll have to do it in the app on your iPhone. Launch the app and tap on the profile icon in the bottom right. Then tap on the gear icon to the right of "Edit Profile" and scroll down until you see "Private Account." Toggle it on.
Instagram continues to expand the Explore tab, giving users new ways to find interesting content. According to the Instagram blog, the latest update brings location and hashtag Stories to the section. The change is one of many that Instagram has rolled out over the past five years since the Explore tab first launched.