India lost because in second innings they relied only on KL Rahul and Pant batting, if remaining batsmen have scored some runs then target would be high for England. The English team got good start in second innings and rest of batting take over responsibility once the opening pair got out. It's a high scoring game as total 1673 runs were scored in both innings which is highest match aggregate for England vs India in Tests. It's a five match series and English camp will be happy to start the series by winning the test.
Yes, you are absolutely right, India scored 364 runs in the second innings, of which Rahul and Pant's runs (137+118)=255 runs
And the remaining batsmen's total (364-255)=109 runs
There was a remarkable partnership throughout the innings, that one between Rahul and Pant of 195 runs. Due to which India's total in the second innings did not go much further. If one or two more good partnerships could have been made, the game would have been a little more exciting.
Anyway, England has batted well this year. Due to which they won the match by 5 wickets.