How to create 2-3 hrs from multiple columns

Question

I’ve a df with multiple time series looks like this

df_observ

id	Date	start time	Action 1 time	end of action2	end Time	Observ1 time	observ2 time	observ1 value	observ2 value
indv1	3-2017	00:00:00	02:40:00	04:25:00	04:38:00	00:05:00	01:45:00	57	111
indv2	11-6-2019	00:00:00	00:46:00	02:16:00	02:40:00	01:01:00	02:37:00	68	113
indv2	13-4-2017	00:00:00	02:22:00	04:25:00	04:38:00	00:05:00	03:10:06	82	125
indv3	23-5-2022	00:00:00	01:34:00	02:22:00	03:34:00	02:24:00	03:25:00	67	101
indv4	8-11-2021	00:00:00	00:05:00	03:16:00	03:52:14	01:01:00	02:11:00	63	108

all-time series are subtracted from the start time. is there a way to plot obsev value changes in different time points ? Thanks!