Add Subscription or individual product to opportunity

    Once you are done with "Configure Account and Opportunity page layouts" You can select Add Subscription or Individual products. These two options will add either an independent plan/charge or a subscription (Selecting  a bundle) to Opportunity. All these plan and charges will be added to Opportunity line Item product list. We can edit these lists after adding if we want to. 
Individual Products :
    This section gives us an option to select only individual plans. This is a product section where we can add the product which is not bundle also which does not have any parent product. Which means, the plan itself is a charge.  
NOTE: This setup uses custom filter visualforce page. Custom filters are not supported in LIGHTNING yet. Even though the org is in Lightning mode, this button asks the user to switch to Classic in a new Tab. 
1) Click on Add Products button under Individual products Related List.
2) Select/Check mark the required products to add to Opportunity and click on SELECT.
3) Enter desired quantity, amount and Opportunity line item product date information in the next screen.
4) these products will be added to Opportunity. We can create an order with these individual products.
     Subscription will provide us an option to add plan and charges at the same time. If we have multiple charges to a single plan, then this button will give us an option to choose those respective charges in a single screen.
1) Click on Add Subscription button under Subscriptions Related List.
2) You will get a Custom page where you can select the plan. Once a plan is selected, you can see the respected charge with other details showed at the bottom of the page. 
These selected Subscriptions will be added to Opportunity as Product list.