The Arduino is a small, affordable, ubiquitous 8-bit microcontroller platform well established as the go-to for simple microcontroller integration. However, after you become comfortable with the platform, you may realize you don't necessarily need everything that comes on a board - In terms of features, cost, or simply mechanical space requirements. Even the smallest Arduinos, such as the Pro Mini and Nano, are dramatically bigger than they need to be to control very simple projects.
There are smaller and cheaper members of the Atmel microcontroller family known as ATTiny, available in either 8 or 14 pin ICs, with various amounts of memory, but with comparable capabilities - the only roadblock to using these with Arduino studio is when bought directly for component vendors, they don't have any of the Arduino bootloaders built in, and you don't generally want them either way because many of the cheaper ones have less memory. Plus, you can't jam them directly into a USB port!
The steps to allow you to use these ICs are relatively simple, and shouldn't be any problem if you're already used to using Arduino Studio. Vadien has taken a step further to simplifying this by offering a pin-to-pin converter board, so all you have to do is source ATTinys in DIP packages, pop them in the socket, and you're off to the races!
Make sure you have drivers for the USB ASP, as this is the USB/serial converter we'll be using to communicate with the ATTiny. Signed drivers that should have no issues installing on Windows are available here.
In Arduino studio, go to File > Preferences, and look for the text box labelled "Additional Board Manager URLs". Manually enter the text "https://raw.githubusercontent.com/damellis/attiny/ide-1.6.x-boards-manager/package_damellis_attiny_index.json" exactly as shown. Credit to David A. Mellis for maintaining this on Github!
Once that's entered, go to Tools > Board >Boards Manager. Search via the textbox above for "attiny", and a package associated with the link above will be shown. Install it!
Now, in the Tools menu, simply set your programmer to "USBasp", and make sure the rest of your board/processor/clock settings are correct for your ICs of choice (this will depend on which ATTiny you chose), and you're ready to go! Note: While using the USB ASP, it is not necessary to set a COM port.
Plug in your USB ASP, your Vadien adapter board, and your ATTiny of choice - then, just program as if it's an Arduino!