Instead of working with remotes Dmitriy suggested to use urls.

app/views/projects/merge_requests/show/_how_to_merge.html.haml

@@ -10,23 +10,19 @@
           - target_remote = @merge_request.target_project.namespace.nil? ? "target" :@merge_request.target_project.namespace.path
           %p
             %strong Step 1.
-            Update the repo and checkout the branch we are going to merge
-            Assuming remote for #{@merge_request.target_project.path_with_namespace} is called #{target_remote}
-            remote for #{@merge_request.source_project_path} is called #{source_remote}
+            Checkout the branch we are going to merge and pull in the code
           %pre.dark
             :preserve
-              git fetch #{source_remote}
-              git fetch #{target_remote}
-              git checkout -b {@merge_request.source_branch} #{source_remote}/#{@merge_request.source_branch}
+              git checkout -b #{@merge_request.source_project_path}-#{@merge_request.source_branch} #{@merge_request.target_branch}
+              git pull #{@merge_request.source_project.http_url_to_repo} #{@merge_request.source_branch}
           %p
             %strong Step 2.
-            Merge the source branch into target branch and push changes to GitLab
+            Merge the branch and push the changes to GitLab
           %pre.dark
             :preserve
-              git checkout #{target_remote}/#{@merge_request.target_branch}
-              git merge --no-ff #{@merge_request.source_branch}
-              git push #{target_remote} #{@merge_request.target_branch}
-              git branch -d {@merge_request.source_branch}
+              git checkout #{@merge_request.target_branch}
+              git merge --no-ff #{@merge_request.source_project_path}-#{@merge_request.source_branch}
+              git push origin #{@merge_request.target_branch}
         - else
           %p
             %strong Step 1.
@@ -34,10 +30,10 @@
           %pre.dark
             :preserve
               git fetch origin
-              git checkout -b #{@merge_request.source_branch}
+              git checkout -b #{@merge_request.source_branch} origin/#{@merge_request.source_branch}
           %p
             %strong Step 2.
-            Merge the source branch into target branch and push changes to GitLab
+            Merge the branch and push the changes to GitLab
           %pre.dark
             :preserve
               git checkout #{@merge_request.target_branch}