1. Add new Instagram account on your phone

1. Open the Instagram app and go to your profile.
2. Now tap the Menu icon in the top right corner and choose Settings.
   
3. Scroll down to the Logins section and tap on Add Account.
   
4. Enter the login credentials for the other account.
5. After doing that, the new account will be added.

To switch between accounts, you just need to do the following:

1. Go to your profile on the Instagram app.
2. Tap the arrow next to your username.
3. Select the account you want to switch to.

2. Use Incognito mode or a different browser

1. Click the Menu icon in your web browser.
2. Now select New Private Window.
   
3. A new window will appear.
4. In the new window, visit Instagram and log in with your second account.

After doing that, you should be able to use two Instagram accounts simultaneously on your PC.

You can also use another browser as a permanent solution. To do that, follow these steps:

1. Open a non-default web browser on your PC, for example, Microsoft Edge.
2. Now visit Instagram and log in with your second account.

Now you can use two Instagram account simultaneously.