上で: a prior step or conditions within an activity
Use the ta-form plus 上で for a prerequisite step and distinguish the dictionary-form use for an activity's perspective. Read a future sentence together with the preceding completion form.
After completing a necessary step
内容を確認した上で、返事をします。 means that the speaker will reply after checking the content. The check is presented as a step preceding the reply, not simply one of two listed actions.
The preceding verb takes the ta-form, but 確認した上で返事をします does not alone establish that the check is already complete. It can describe an action to be completed before a future reply.
Noun connections and simple sequence
家族との相談の上で、決めます。 means deciding after consulting one's family. A procedural noun such as 相談 can connect with の上で.
昼ご飯を食べてから、散歩しました。 naturally gives the sequence of lunch followed by a walk. 上で highlights the first action as a preparatory step for a later decision or action, so not every てから needs to be replaced.
The dictionary form can frame an activity
日本で生活する上で、言葉の知識は役立ちます。 says that language knowledge helps in living in Japan. It does not put that benefit after living there has entirely ended.
比較した上で選びます gives the procedure of comparing first and then choosing. 選ぶ上で大切な点 identifies points important when choosing, so check both the verb form before 上で and what follows.
Quick check: Does 説明を聞いた上で、申し込んでください。 ask you to apply first and hear the explanation later?
Show the answer and why
No. It asks you to hear the explanation first and then apply. 聞いた expresses completion preceding the application.