add help info (#142)

web/src/pages/chat/chat-configuration-modal/prompt-engine.tsx

@@ -154,7 +154,7 @@ const PromptEngine = (
       <Form.Item
         label="System"
         rules={[{ required: true, message: 'Please input!' }]}
-        tooltip="coming soon"
+        tooltip="Instructions you need LLM to follow when LLM answers questions, like charactor design, answer length and answer language etc."
         name={['prompt_config', 'system']}
         initialValue={`你是一个智能助手，请总结知识库的内容来回答问题，请列举知识库中的数据详细回答。当所有知识库内容都与问题无关时，你的回答必须包括“知识库中未找到您要的答案！”这句话。回答需要考虑聊天历史。
         以下是知识库：
@@ -166,10 +166,10 @@ const PromptEngine = (
       <Divider></Divider>
       <SimilaritySlider isTooltipShown></SimilaritySlider>
       <Form.Item<FieldType>
-        label="Top n"
+        label="Top N"
         name={'top_n'}
         initialValue={8}
-        tooltip={'xxx'}
+        tooltip={`Not all the chunks whose similarity score is above the 'simialrity threashold' will be feed to LLMs. LLM can only see these 'Top N' chunks.`}
       >
         <Slider max={30} />
       </Form.Item>
@@ -178,7 +178,10 @@ const PromptEngine = (
           <Col span={7} className={styles.variableAlign}>
             <label className={styles.variableLabel}>
               Variables
-              <Tooltip title="coming soon">
+              <Tooltip title="If you use dialog APIs, the varialbes might help you chat with your clients with different strategies. 
+              The variables are used to fill-in the 'System' part in prompt in order to give LLM a hint.
+              The 'knowledge' is a very special variable which will be filled-in with the retrieved chunks.
+              All the variables in 'System' should be curly bracketed.">
                 <QuestionCircleOutlined className={styles.variableIcon} />
               </Tooltip>
             </label>