Step 1: Navigate to Templates > Add New.
Step 2: Choose Archive template and name it if you want, click on Create Template.
Step 3: Close the popup box, search for Blog element then drag it into the section.
Step 4: Select Query section and turn on Main Query.
Step 5: Hit Publish to save and Add conditions.
Note: To create a Custom Portfolio Archive Page, do as the same steps as above except for Step 3, search for the Portfolio element instead of Blog then drag it into the section.