Run time in minutes - with Datetime (only minutes) input box from Home Assistant

Hi,
Im looking for a way to input time (eg a number of minutes) into a sequence to turn off a relay after the set amount of time. I want to be able to set this time from home assistant dashboard so it is variable.
I have manged to put a sequence together to start the relay at the set time in HA.
Ideally I am looking to run series of relays after one another as well as set the days of operation as well as the relay numbers on or off (ie skip) through some boolean switches. This is my first attempt on HA and Node Red so appoligise for my lack of knowledge.
Any help would be greatly appreciated.
I have attached a screen shot of my dashboard and my node red code

[{"id":"7f1ae9f5cadbbc1f","type":"tab","label":"Flow 8","disabled":false,"info":""},{"id":"54a0d3a9afa31c2c","type":"ha-time","z":"7f1ae9f5cadbbc1f","name":"","server":"e7f83bdc.15f068","version":0,"exposeToHomeAssistant":false,"haConfig":[{"property":"name","value":""},{"property":"icon","value":""}],"entityId":"input_datetime.only_time1","property":"state","offset":0,"offsetType":"num","offsetUnits":"minutes","randomOffset":false,"repeatDaily":false,"payload":"on","payloadType":"str","debugenabled":true,"x":190,"y":140,"wires":[["14507e41fc08d063"]]},{"id":"6923805ef4d6ebe5","type":"debug","z":"7f1ae9f5cadbbc1f","name":"do stuff","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"payload","targetType":"msg","statusVal":"","statusType":"auto","x":940,"y":100,"wires":[]},{"id":"14507e41fc08d063","type":"switch","z":"7f1ae9f5cadbbc1f","name":"Switch on Relay 1","property":"payload","propertyType":"msg","rules":[{"t":"eq","v":"on","vt":"str"}],"checkall":"true","repair":false,"outputs":1,"x":490,"y":140,"wires":[["6923805ef4d6ebe5","4e859c84fd82626d","ea4e0bada7b60d0c"]]},{"id":"4e859c84fd82626d","type":"api-call-service","z":"7f1ae9f5cadbbc1f","name":"","server":"e7f83bdc.15f068","version":3,"debugenabled":false,"service_domain":"switch","service":"turn_on","entityId":"switch.relay_1","data":"","dataType":"jsonata","mergecontext":"","mustacheAltTags":false,"outputProperties":[],"queue":"none","x":930,"y":160,"wires":[[]]},{"id":"ea4e0bada7b60d0c","type":"ha-wait-until","z":"7f1ae9f5cadbbc1f","name":"","server":"e7f83bdc.15f068","version":0,"outputs":1,"entityId":"input_datetime.runtime1_1","entityIdFilterType":"exact","property":"entity_id","comparator":"is","value":"","valueType":"str","timeout":0,"timeoutType":"num","timeoutUnits":"seconds","entityLocation":"","entityLocationType":"none","checkCurrentState":true,"blockInputOverrides":true,"x":680,"y":200,"wires":[["358e06f7d789af3f","5b9b633af87b600d"]]},{"id":"358e06f7d789af3f","type":"api-call-service","z":"7f1ae9f5cadbbc1f","name":"","server":"e7f83bdc.15f068","version":3,"debugenabled":false,"service_domain":"switch","service":"turn_off","entityId":"switch.relay_1","data":"","dataType":"jsonata","mergecontext":"","mustacheAltTags":false,"outputProperties":[],"queue":"none","x":950,"y":240,"wires":[[]]},{"id":"5b9b633af87b600d","type":"debug","z":"7f1ae9f5cadbbc1f","name":"do stuff","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"payload","targetType":"msg","statusVal":"","statusType":"auto","x":960,"y":360,"wires":[]},{"id":"e7f83bdc.15f068","type":"server","name":"Home Assistant","version":1,"legacy":false,"addon":true,"rejectUnauthorizedCerts":true,"ha_boolean":"y|yes|true|on|home|open","connectionDelay":true,"cacheJson":true}]

Thanks Danny