From the Merge & fix page, see all of your contacts with the same first and last name. From here, you can select which contacts to merge (or simply merge all of them).
Now available on Dex Mobile, merge and fix operates similarly to the Desktop app! Simply navigate to the merge and fix section on the bottom right, and merge contacts with the same first and last name!
On the contacts page, you can select multiple contacts that you want to merge. For example, a contact may have different display names on Facebook and LinkedIn. Simply press "M" to merge these contacts or click the merge button at the top toolbar.