From their website. I think this is the proper product. The same instructions should have come with the product you bought, I would hope.
Install EternaSeam over the repair area, removing the release liner
gradually to prevent contamination of the adhesive prior to application.
Rub or roll with pressure using your hand or a steel roller to activate
bonding process. This material may be applied to clean dry surfaces
from 150°F to -20°F ambient. Treat surface with EternaPrime for
installations from 40°F to -20°F ambient.
75 E. Division
Mundelein, IL, USA