Tethering on Micromax Doodle 3 should not be any different than any other Android device. You would however need a WiFi adapter on your PC to be able to tether and access internet on the PC.
Here are the steps to connect your handset to your PC for internet access:
On your Micromax Canvas Doodle 3:
1. Head onto Settings.
2. Wireless & Networks > Tethering & Portable Hotspot
3. Select Setup WiFi Hotspot
4. Enter the required details (SSID, Password etc) and Save.
5. Now select the option Portable WiFi hotspot to enable it.
On your PC:
1. Scan for the WiFi network SSID you just setup on the phone.
2. Enter password.
That's it. You would now be able to access your phone's 3G data on your PC.