This article highlights the steps necessary to install the mod manually. Please note that manual installation is intended only for people who cannot use M3 - it needs not to be used when M3 install is appropriate. You will still need to use Legendary Explorer to apply some of the necessary edits, which has pretty much the same hardware requirements as the Mod Manager. Therefore, Linux users will need to use a Win7 or later Virtual Machine / PC, and copy the edited file back into their game later.

Unpack the 7zip from the Nexus download. Copy paste the DLC_MOD_AsariDash folder to Mass Effect 2\BioGame\DLC folder in case of OT, Mass Effect Legendary Edition\Game\ME2\BioGame\DLC in case of LE.
In case you mod the OT, you also need to install the binkw32 bypass

Go to the freshly pasted folder, open DLC_MOD_AsariDash\CookedPCConsole\BioGame.ini file. Switch any settings to your wish. This file contains all settings M3 users would see during their mod installation, and several more tweaks.

You need to download Legendary Explorer, of at least version 6.0:
Link to the minimum version.
Link to the newest version.

Open the SFXGame.pcc file, located in Mass Effect 2\BioGame\CookedPC in case of OT, Mass Effect Legendary Edition\Game\ME2\BioGame\CookedPCConsole in case of LE.
Follow the SFXGame edits article to get the code edits you will need apply.