Follow the next steps to install M2E Pro:
Step 1. Install Composer Installer. It automatically installs/upgrades those modules which are provided as dependent packages in the Composer project of your Magento.
Step 2. Provide the Composer Installer as a dependence on the composer.json file of your project. Use the following command:
Step 3. To complete the process, run the commands below:
That's it! M2E Pro has been successfully installed.
Provide the initial configuration of the selected Integration and enjoy your sales on Marketplaces via M2E Pro.
This instruction does not contain any recommendations for enabling the Maintenance Mode in your Magento. The decision is up to you.
If you face any issues during the installation process, read this article to find the solution.