Adding a new contact
You can add a new contact from the contacts or call tabs. Go to your Contacts+ app, Select the '+' icon > Choose 'Contact' > Fill the contact fields > Tap the '✓' option on the top right corner to save the contact.
You can also add a contact from the call-log screen by choosing the '⋮' option (to the right corner of the phone number) and then choose the '+/Add to contacts' option.
Please find the following .gif file with the procedure (just for your reference):