Once you have bought your smallcase, and want to increase your exposure to it - you can invest more in your smallcase
From your Investments page, click on any smallcase and you will have the option to Invest More in its right.
The Invest More page helps you buy more of what you currently hold, meaning it will have a minimum amount to maintain the weighting scheme. You can increase this amount to invest whatever amount you like, and it will be adjusted to the closest amount required to maintain the weights
You can use this functionality to double down on your investments anytime you like. You can also invest more through SIP
smallcase is about helping you manage your portfolios seamlessly. You can also add certain stocks or shares to your smallcase
For more on how to do this, you can see here
Caution: Adding stocks or shares from your smallcase means it will not match the original version, and hence the holdings, composition & returns of your smallcase will be different. Only proceed with managing your smallcase, if you know what you're doing. Not recommended for first-timers :)