Your profile holds all your information and updating it is really simple.
Hit the settings cog in the menu bar and use the menu that appears to select Edit Profile. In the Blink mobile apps, the settings cog can be found top-right of the Feed page.
This opens your profile, fill in anything that's missing and you're good to go. Only people you're connected to can see your full information.
On the preferences tab of your settings page, you can choose to hide your contact details which will mask all of them from your contacts. This is useful if you have signed up with a personal email address and joined a work team.