Errm the very first post shows how to set things up as you want them using input_select, but if you read thru’ the thread it show how to do it using input_sliders (now renamed to input_number - but they do the same thing and the code is the same).
So…
in input_number.yaml
alarmhour:
name: Alarm Hour
icon: mdi:timer
initial: 06
min: 0
max: 23
step: 1
alarmmins:
name: Alarm Minutes
icon: mdi:timer
initial: 00
min: 0
max: 59
step: 1
alarmfinishhr:
name: Finish Hour
icon: mdi:watch-export
initial: 07
min: 0
max: 23
step: 1
alarmfinishmins:
name: Finish Minutes
icon: mdi:watch-export
initial: 05
min: 0
max: 55
step: 5
Automation.yaml
###############################################################################################
# #
# Alarm Clock #
# #
# #
###############################################################################################
- alias: 'Wake Me Up'
initial_state: 'on'
trigger:
- platform: time
minutes: '/1'
seconds: '0'
condition:
condition: or
conditions:
- condition: and
conditions:
- condition: state
entity_id: input_boolean.alarmstatus
state: 'on'
- condition: state
entity_id: input_boolean.alarmweekday
state: 'on'
- condition: time
weekday:
- mon
- tue
- wed
- thu
- fri
- sat
- condition: template
value_template: '{{ now().time().strftime("%R") == states.sensor.alarm_time.state }}'
- condition: and
conditions:
- condition: state
entity_id: input_boolean.alarmstatus
state: 'on'
- condition: state
entity_id: input_boolean.alarmweekday
state: 'off'
- condition: template
value_template: '{{ now().time().strftime("%R") == states.sensor.alarm_time.state }}'
action:
- service: tts.google_say
data:
entity_id: media_player.speaker_1
message: "Good morning Sir. Time to Wake Up!"
- service: switch.turn_on
entity_id:
- switch.zw_bedroomsunlamp_switch
- switch.rfl_bedroom_pcmonitorandsound
- service: light.turn_on
entity_id:
- light.rfl_bedroom_ceiling_light
- light.rfl_bedroom_uplightredbottomlamp
- service: light.turn_on
data:
entity_id: light.zw_uplight_dimmer_level
brightness_pct: 70
- delay: '00:00:20'
- service: switch.turn_on
entity_id: switch.veho_power
- alias: Turn off Alarm
initial_state: 'on'
trigger:
- platform: time
minutes: '/1'
seconds: '0'
condition:
- condition: template
value_template: '{{ now().time().strftime("%R") == states.sensor.alarm_time_fin.state }}'
action:
- service: homeassistant.turn_off
entity_id:
- light.rfl_bedroom_ceiling_light
- light.rfl_bedroom_uplightredbottomlamp
- switch.zw_bedroomsunlamp_switch
- switch.rfl_bedroom_pcmonitorandsound
- switch.zw_tvandsoundbar_switch
I have an input_boolean to turn it on and off as well. There are other ways probably more efficient but this works. There are new components which would probably make this better but I haven’t got round to looking at them yet. The alarm thread does have many other examples of how you could achieve what you want.
Hopefully that helps you get yours setup 
The card in the frontend looks like this…
