Using the top "Create" button"

In order to create a new Test Issue, 

Click the Create Issue at the top of the screen to open the Create Issue dialog box / page.

Step 2: Select the  Project  and on  Issue Type,  select Test.

Step 3: Under the General tab, type a Summary for the test and fill all appropriate fields — at least, the mandatory ones marked with an asterisk.

Step 4: On the Test Details tab, select the Test Type and complete all appropriate fields;

- Select the Test Type as Manual. 
- After filling out the Manual Steps fields, press the Add button to jump to the next Manual Step. 
- Use the Pencil button to edit a previously entered Manual Step, and press the Update button when done. 
- Use the Bin button to delete a previous entered Manual Step.
- To change a Manual Step position in the Test, drag the left area of the row and drop it to the desired place.

At 

From the requirement issue screen

In order to create a new Test Issue directly from the requirement issue screen, and link it automatically to the requirement, 

Step 1: Click the Create Issue at the top of the screen to open the Create Issue dialog box / page.

Step 2: Select the  Project and on Issue Type make sure you have Test selected.

Step 3: Under the General tab, type a Summary for the test and fill all appropriate fields — at least, the mandatory ones marked with an asterisk.